Machine gun



Jan. 15, 1935. A. J. LAHTl 1,937,939

MACHINE GUN Filed July 2 8, 1933 2 Sheets-Sheet 1 ililillll PatentedJan. 15 1935 PATENT OFFICE MACHINE GUN V A V Aimo Johannes Lahti,JyvaskyIa, Finland Application July 2s, 1933, Si n No. 682,711

In Finland May 22, 1933 3 Claims. (C l 42-4) It isik-nown that troublessuch as occur in the use of machine gunsconstructed according to therecoil system, are due to the large number of parts and the thuscomplicated construction of 2'5; the same.

Another objection, especially as to machine guns of large caliber isthat the operator on setting the lock piece is compelled topullsimultofore it-has not Ibeen possible to set the lock piece withoutmoving the sliding device and the barrel.

g The imprbvedymachine gun constructed according-r to..-my invention iscomposed of a much 1 smaller number of: parts than any other machinegun; may bev readilyoperatedand is not likely to getjout of order.

Another -advantage gained by my improved machinegun is that ,it is nowpossible, solely by changing the magazine support, to use both straightand gcylindrical magazines and, if also thebarrel .is changed, to firewith cartridges of various calibers.,, Further, the mechanism is soconstructed,.th'at the same can be used also for r the largestsize ofcartridges in machine guns of large caliben. ,1 i l In-the machine gunaccording to my invention the barrel and the sliding device are rigidlyconnected and, move a, short distance to and fro. The sliding device isof improved construction and such that the lock piece, the lock pressingrod, the cooking bolt, the bolting piece, and the bolting piecedepressor are situated inside and are movable with the same. Theconstruction is such that the machine gun may be set automaticallysolely by the aid of the lock pressing rod without moving the slidingdevice and the barrel. The rigid connection between the barrel and thelock piece is established when the lock piece has moved so far forwardthat the setting sill of the lock pressing rod has forced the rear endof the bolting piece to rise in front of the support cam of the slidingdevice, the setting sill establishing the rigid connection. The movementof the cocking bolt being compulsory and simultaneous with that ofthelock pressing rod, the cooking bolt will immediately, as soon as therigid connection has been established, hit the percussion cap, and it isthus impossible that an unexploded cartridge could remain in the hotbarrel.

By the influence of the recoil caused by the powder gases the front wallof the sliding device will strike against the upper end of theconnecting lever and said lever will again strike against the lockpressing rod with such force that said gtaneously ,all of the interiormechanism, as here-;

rod will be brought into its rear position with its'spring compressed.When the lock pressing rod movesrearwardly the rigid connection isbroken and the bolting piece depressor will press down the boltingpiece.

The accompanying drawingsillustrate an embodiment of'the machine gunaccording to the invention.

Fig.1 is a side elevation of my improved machine gun. I

Fig. 2 is a longitudinal section of thesame.

Fig. 3 is a detail side elevation of the lock pressing rod.

Fig. 4 isa detail plan of the'same.

Figs. 5 and 6 are detail elevations of the bolting piece depressor.

Preparatory to firing, the machine gun is set by the aid of a settinglever l which is movable in a groove-of the bottom of the casing. Onpull ing the setting lever '1 rearwardly the stud 1c of the settinglever moves rearwardly in the slot 211. in the under side of the lockpressing rod 2 until it reaches the rear end of said slot and then pullsthe" lock pressing'rod 2 rearwardly, the setting sill Zbbeing movedalong the lock pressing rod 2 which is under the bolting piece. Thecocking bolt 13 that is anchored, between the abutments 2h and 21' ofthe lock piece 6 will be compelled togfollowthe movement of the lockpressing rod so that on the latter moving rearwardly the point of thecocking bolt 13 is pulled into the lock piece 6. The lock pressing rod 2having moved so far rearwardly that the bevelled surfaces 20 of thegrooves in the sides of the lock pressing rod engage the abutments 4a ofthe lower arms of the bolting piece depressor 4, the bolting piecedepressor will be pressed down thereby also compelling the rear end 3aof the bolting piece 3 that is supported against the supporting surface5a of the sliding device 5 to move downwardly. The rigid connection ishence broken and the lock piece 6 will now follow the movement of thelock pressing rod 2 rearwardly. The barrel 7 and the sliding device 5,threaded together that have not been moved during the setting, are heldagainst casual movement by the spring 8 of the pressing rod 9 of thesliding device. When the lock pressing rod 2 has moved so far rearwardlythat the setting sill of the holder 10 of the lock pressing rod hasrisen in front of the setting shoulder 21 of the lock pressing rod 2 themachine gun is cooked and the spring 11 of the lock pressing rod 2 thatalso acts as cocking spring, is likewise set.

Now the magazine may be inserted in the known manner.

The cartridge is fired by pulling the trigger 12, which releases theholder 10 of the lock pressing rod, so that the set lock pressing rod 2is freed. The spring 11 thereupon forcibly moves said rod 2 forwardly.The lock pressing rod 2 moves the lock piece 6 forwardly therewith, sothat the bolting piece 3 is lowered and the bevelled surface 31) at thelower face of the bolting piece, 3 lies against the bevelled surface ofthe setting sill of the lock pressing rod. The upper face of the slidingdevice 5 preventsthe bolting piece from rising which it tends to doduring the forward movement of the lock piece.

The forward movement of the lock piece 6 thrusts the cartridge into thebreech chamber of the barrel.

When the lock piece 6 has reached its fore-,

most position the bevelled surface 29 of the setting sill of the lockpressing rod 2 serves to lift the rear end 3a of the bolting piece 3against the support surface 5a of the sliding device 5, and hence therigid connection between the barrel 7 and the lock piece 6 isestablished. Now, when the lock pressing rod 2 moves further forwardly,its setting sill 2b reaches a point under the rear end 3a of the boltingpiece 3 and thereby prevents falling of the bolting piece 3, thusestablishing the rigid connection. After the rigid connection has beensecured and the lock pressing rod 2 moves further forwardly the cockingbolt 13, situated between the abutments 2h, 2i of the lock pressing rod2, strikes the percussion cap and the cartridge is fired.

When the cartridge has been fired the barrel 7, the sliding device 5 andthe lock piece 6 begin their rearward movement while the rigidconnection between the barrel 7 and the lock piece 6 is still unbroken.While the sliding device 5 is moving backwardly its front wall 5bpresses the connecting lever 14 rearwardly so that its upper end 1411gives the lock pressing rod 2 a rearwardpush.

When the lock pressing rod 2 moves rearwardly the abutments 2h, 2ion itsupper face compel the cockingbolt 13 to be pulled into the lock piece6.- While the lock pressing rod 2 continues its rearward movement theparts will operate in the same manner as described above with referenceto the setting, with the exception, however, that the batrel 7 and thesliding device 5, as soon as the rigid connection has been broken, willby the action of the pressing rod 9 of the sliding device return intotheir foremost position.

In rapid firing the machine gun continues to operate as long as thetrigger is being pulled.

I claim:

1. In a firearm of the class described, a casing, a barrel arranged forlongitudinal movement, a lock pressing rod longitudinally movable in thecasing and having a cam, a spring to move the lock pressing rodforwardly, a lock piece on the lock pressing rod, movable therewith andalso movable to a limited extent longitudinally and independently ofsaid lock pressing rod, a bolting piece arranged at the rear end of thelock piece, pivotally connected thereto, and movable by the cam of. thelock pressing rod, a firing pin carried by the lock piece, movablelongitudinally to a limited extent independently thereof and alsomovable to a limited extent by the lock pressing rod, a sliding devicein rear of the lock piece and engageable by the bolting piece when thelatter is moved by the cam of the lock pressing rod during forwardmovement of the latter to thereby effect a rigid connection between thelock piece and the breech of the barrel, a spring to prevent casualrearward movement of the sliding device and'trigger mechanism to lockthe lock pressing rod in cocked position against the compression of itsspring.

2. A'firearm as claimed in claim 1,.including a bolting piece presserarranged between the rear end of the lock piece and the front end of thesliding device and arranged above the bolting piece, said bolting piecepresser having a depending arm provided with an inwardly extending lugand said lock pressing rod having a groove in one side in which said lugoperates.

3. A firearm as claimed in claim 1, in which the firing pin has arearwardly extending arm provided with an enlarged portion and the lockpressing rod has a pair of spaced shoulders between which said enlargedportion of said arm is arranged, the space between said shoulders beingsomewhat longer than said enlarged portion of said arm.

AIMO JOHANNES LAHTI.

